SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a0b258b33644b7f8b2c093386b720351185bf509f15a25be9b6b3cc875615ef' 
  AND token = 'fNR7aGsnHHCUhkNJIoIgyyO1FFiZyusuHnHQ2rMGSZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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