SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cc79d842272218ee0b743a5a7c704164da88a3c02689bcc579d0eaa16982bf9' 
  AND token = 'LvsRHKcpWAoHsVT20MlPjihbfuSnznF/wXxjHUhHhWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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