SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69892ad80d32b2c9b1611a057614d885ed7093d4248ccb55ed28eedc84910254' 
  AND token = 'QDK6MzxlyYW+o1OlpGqLUnfqmv/EUvg3LAUZScvIt3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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