SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f4163fe9d001fb9631e127f49b6dc60df841245ca70955f45388b65a3a69928' 
  AND token = 'q4+gBYZUq51D+YcMvyciAnGXSnkEOTZcspVV3xxAJ/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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