SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd849a8704dd53c6f9128e624315d9a0f7e0ab88d41843506a3b8755098b60bf3' 
  AND token = 'T66nOxx2GhQPHNmkuE2IWsqp0tHvUpm0wXdLMHtUZBs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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