SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c57b84c52d6b331a43853700ec85957ff1c276bde84a890d5aeadbe984e122a8' 
  AND token = '68UtARGNOZjHXViYyIYoRXZHIcFDL6Zq7kqTBN+UJBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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