SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c3967984d926d0361cc196cf1c509f34c52e0ce3fce3a0127608e84700ca31d' 
  AND token = '1UhFwIbK/UW/T0VJ3ReqKyiDpPQOVpuzydXgKKGmfJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}