SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da98cfa15a06fd40ce058c982f975962773fdb441c2f3e35e75d7bfc0e7d66dd' 
  AND token = 'DcMowZbqMxXVjmnZZ6UWmwJCnJoM+qgADYmg4hkZFkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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