SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '1d8038fbc8f5084a65b2537804e0d350eb70f56c650056881089ee75b488c927' 
  AND token = 'wMUhNz+DBc/iKuzYRo/xCGx764/05gdEvlFd3ENSM8Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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