SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7f7dd76d2079ef1e106f10a9d8b783b72f9fff9bfa2773bcf51122d9ea1a5a8' 
  AND token = 'rguk7P/ROXzxtKJx2fF1ga60VHpi8NcKyei2vGk7btM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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