SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8a955342d82c018b307594234b769ac46d38a758db4051d5a2ffb5575d6bf6a' 
  AND token = 'YLcnrOfcb+RiW7yGFNfQ6u2wE+z7EKFjqHsFhxzRZR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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