SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d5e0b91146f61778e3fdc2461d07dec99389d450ca255da0d8429c9bd8e2da4' 
  AND token = '1qPNAHTa0lPHV6zOvLGyiljJ3HQyXxfo0LtiWLnGFXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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