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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9ccc1e9dbf3dd95676b5ae3408f8c5d6848b96c38334eb6603d8d04fb200a65' 
  AND token = 'uI6dRCRrUjuce1LiRknkLKHQs1GIPxl/EICYWmhujJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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