SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23213386b01feb70e6682f0ff858e3748084cb679abbf3c472012c8218e36b50' 
  AND token = 'iKe7nv3Bf0LJ+BkDvchXgJpMoootkRQnSreosfflDRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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