SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3aa4d6e58adafda1396838f4ca2d979503ab05fe4b7382d54cc792b3f5f6ee28' 
  AND token = 'qMLtnlUh4mGpM6wMKZXw4gbzO+OK7LOEkwuhxTQYROM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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