SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7f4a3d12dcac2222a646abf0aa01b296983ceec159989792329835c9dcafa86' 
  AND token = 'O8RyG1U1flpMb7FXd4EVr9s7nXJzwn+OhvYnBPK5jCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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