SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'cffd9b932783114beb9a569a118710af1a46901105a12456e90a3ec98ae23a87' 
  AND token = 'dHBxkUMTJw6cO+RSOiuVCgmz0JWNXzexuGCNwV67Whw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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