SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a016f937505814332ec9ed2a46881345720e5e46e93b9cf3ec3d56818a5754d' 
  AND token = '8bcsu3vPGgZXFY7xudb6wKMLERL5qU/eKjFxXt58zxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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