SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ab40b402172f412ca781dba7073faf702eb278f3abde5339bcca99298c89beb' 
  AND token = 'Y+rZQQfH7h3G6CvZnQNetg5Tvv7Gh/WJNLr6ruJdLBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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