SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6500f7cf88e6319661b072b4088c829b95bab28d3e709e38b262bc0c3092606d' 
  AND token = 'BhOhFQanIvRSCZeCDB/CsTQ20RbezkeyoA8xrpEqIv8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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