SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18a8ba96beb862356c82b846e4dd47725af3527f17ddb0b654701471783a5a7b' 
  AND token = 'OUQzXkfju0HE2+4HvpqIOo/fEJ1VsaIDyhuWEWhCqvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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