SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81268974a67f5f4aef540822751214b65cfa00bd995d18ef37193e33f7d5b35c' 
  AND token = 'IkgeSpj7lJgKxe4qUiIa6Ehp8ZnE/cCABl+mSYbWVaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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