SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f4ef7646a45aa7fd46e3e253305745d6c9c28f2db0030c25079ff255b2a3e2de' 
  AND token = '6Do5P8ZCKNHqeBvTS3GJvoY1JYW6z9AdGgefqSv5CCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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