SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b718de7f92832b88c60c272c61740ec04eef9a11b72e6bf7cddbdc697f0ca207' 
  AND token = 'gaA2ysgM76znn8xyJHdk7oypMLgr1P7IEB0e8xFYyJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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