SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2db3ed6e6fd0b45633a19b60ab0ece1b1061a97dcb8a83902355acb6f5643227' 
  AND token = 'h9EczCY8F5DV1OGBcSMHJ9LfdKcYLJ4SInParwqs/vk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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