SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '3bc66a2102f1fbe89bc5f13c3f199ac83f427480ba17c1024f98c3e6855bc116' 
  AND token = '4triviKvoQUrhgaF6chWRki+GuHucDHSVsNBR48sOIo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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