SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a4df02ab4d9b26f4190c05587f3d94c17055a27e786fc98dfc194e77c14050ca' 
  AND token = 'TknAHUVDIiVF9jQXrYBuH39Hp4IW7B2VM2NoBNuf5kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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