SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfe93aee1a705d815df2489740e17928552183ff3fe473c090b572676214222b' 
  AND token = 'WuTorfj12yFzDd6jHRdUA3apYESgNuzdOWz3ZciZg/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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