SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5af60c5a6af36ad5f8d7777a80e2943d8072bcc318cea253b969d0a7970a52f' 
  AND token = 'G9ixGCs6B+SauhLkJGqUH/QGBzWLv0fLDO3fI0QN98o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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