SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8daebe9d71db7abe1481ba6360c0669da848ecb6a2eb06d42b2bfc3aafbc138' 
  AND token = 'WiRUhfAGY2cktr3kYx/J6JsqcNE69Y3gmkBjidxPa4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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