SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9767bff1c1e17add80ecd807e5fab0d2ab9121ad6a789e1c09159e1164b1d895' 
  AND token = 'VSffibq2VqAcTOOUDVQBGmxMN0H++6Mz/iJJ/wDCYjk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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