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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6df8c1e7478ea1beb66eb90093a5b3f60a595f711217424c9dac4a324244c90' 
  AND token = 'YJDLg6IcGl0xWiBgNQO+dgMKHmcXfqY99fWZf61Ktkw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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