SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91aaa7c17ca3ae27c21edda28f9369935a3dfecd847018438741180c5232054a' 
  AND token = 'oHF+5xnDQgPChSsMDTV0FBh2jV2yqSQSGr+dT/yWZ54=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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