SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1618325c5fdb9f714dbee697cfbc75079e43e431f12dd4eb6184efdaae673a6' 
  AND token = 'FrYIyGUnzwJcUHHAaPJhnZQDzeDlV8a/XsLtlunt148=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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