SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd14a21c727287f15abed9c6ac94db6070aea565f983d29cfeff487506f9381a0' 
  AND token = 'm4XWsNd/QVM5uzwiunICyUMrlXhwJmBM+0Y9v7AgfKM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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