SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48a232cb24359f0781afb0ea694c11494606b63ae6d9348e04e24eb49067ad01' 
  AND token = 'VKztkrtsn8sfJ4lk7lUGDwUf8CFETzuBsEaQsHMgk2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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