SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9afce8a55bee991cdfaba01685f14aa51aa483431f3a99a45da6c6f63ee0a1c' 
  AND token = 'jAYFQjUuX/fqARxUPi+NAOggMmosJQiUQurp1mrcapc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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