SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5322d60ea77126ede7cfb14515a1af4b5792e9c760faa0d431bbe297328f4789' 
  AND token = '/t/QwkFH6rgqmth1FEHei5Sm3QjIsGWCxAnrphXlZLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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