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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3d4b635402663dc07b18ac088d177b6cf72b6c2c4697979a37ba75d4a031bd0' 
  AND token = 'uC1xGNOMkLJNz3sUNsDGVL+x/lJ1YX1pUX+5/rAlC78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}