SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49f5d782d2564e24595c0eaccc2ce70ebcb7be0e1ffbbb62b719a39869028438' 
  AND token = 'METzeYLHdYWrgXZpG1N68J+HaCcfKW6vwdjwaoNXhk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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