SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42a2119ce863364aa50e97c46636aa5f4fa920d19579bab9b7fa2b8510f993d1' 
  AND token = 'snO8oqiwNiWIV5gFVyRSXjgK9WP9zFlPXYpMCdUVbfw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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