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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5dfce23cd1e468e85612ca95f48aafcb8fe886bcd69cb2b2dc1cd6435e045d73' 
  AND token = '5uG3+ciq0F5kLaZDLt4FPQ5M0HHtCsMMLeDqKQP0eZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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