SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '386ce64bcc812f0491b8e48a846cf4f71b47ae3c333d89da484f94d6beeee2c1' 
  AND token = 'kLR561sffrNFE2etqBR+UkzXHjTPZKR/H29TtBr7/9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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