SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0948abd2f8175204b94dfb2e5ac66069ed50e1867de3faa05cb113a10a507531' 
  AND token = 'lpzhD3SIvadApGMHYChajZ9dup8HPwwf6pBgGVmJcdw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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