SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d01a3074441bd30ad5504921c31413146d2204b4939982c9e5d8302cd7debb1' 
  AND token = 'a775lis5qmqvUGpFO5qBnIggcWCEt+A019H5IhdePwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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