SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '543f8f3f95932246e48d7fb331860d6f600509d17fc1228d797d1c3a9bfb7f97' 
  AND token = 'LiYUKCrltixtfG3tz4IqlCRMXVDOmwitDuZJuz0RPFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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