SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d6c8edc3e3e75101d513581d8c125b46a98900ee4b662f32ee95b3fb8446f1f' 
  AND token = 'Cn8Bfqhj5NqO3PbSxOfFOxZs37zlarbZmtuQY0by8Sc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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