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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd1550b5324802d7c6b251aabb2b18dc840cea00099bfd9fdf40940983c1c100' 
  AND token = 'TEg+8rdcWFKW4mwwqlSLD7dAQAo1UTpN6sOA7Y+WwMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}