SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fa6814f11f3bee9357f123accff841caf1f1c11ecfa6f76f9328d4d906c4f77' 
  AND token = 'm0zJhsPv+wEhvlTcSbN8htuz+AF7nSLzOtaysNnBH4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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