SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b18e75cc887b7b9ba73c0b722e760b98d71fce6dcd51fb4429aff47a63f70e34' 
  AND token = 'o11cPBzOhAXMJwJCf8ZZ6Wp6U/uSN+SGI8exbIv0n1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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