SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c3d5ade24bc634dc1236b8e0eeb1b128a2642ae9bef5749f41ec20a9d998b7a' 
  AND token = 'lLbgEumoNQtANEPzNSgtybqP7wij0Y9g2vxJR+2sSo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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