SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '048fa6fef674f2d877cba998ffd056543e17c88f716426884c11cadf859a5633' 
  AND token = '+JVlf0uYmWz/+r8U8Pm5700IBJMsgqUhgwkW0Gy7bzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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