SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfe35a76a869152de8e529a2f10901d68fa74929926fc384f83de43178cc108e' 
  AND token = 'XuAVYZQjAhVLuNtNFrf7tzLtcj9byhXNdpD3Iho91Qo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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