SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49192982a342e1136b65f221904fe5adcd84f906fc59069220563dda039a73b5' 
  AND token = 'ZKiSFe9tyfvYjRVHSfvhObwdPu/xW11JuxngnrG5LlU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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