SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1e667c74547968aa289efa03bf7041ccf149131a44751408d93d681bb1f8a25' 
  AND token = 'sbeXCFbXs825ZiHYpXLVsCVNprFWgihZni/UJoIb+QQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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