SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19846fea4d484d30d527e9d1b8b8a147be84bf3b97c6f7b316e32e26f14e131b' 
  AND token = 'XWz60g07STLF2y+jgqgPCYnF59/nDQNL/hjSmwVk4aQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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