SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0279fc77e15d754a42e1ee2ece3c4ad788703af750376f201123d2b245470e59' 
  AND token = 'TuQhGgAsRYptpcq1DDTfpaCSBw8P7ErwRaYrr2mSkEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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