SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f5c93092f075a77653aae613602a1f8c41174ed31bdca054f015c8974fd5d879' 
  AND token = 'dBkdvrrhapBhXTMStdjfXqjh7UE5x2dbQk2nLDC0GS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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