SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa1caa1e76203853c10970a3f92f834f1155312fcd8bbbc8223b0ba5c6363678' 
  AND token = 'runHn781FWHnZ1KJxatLcXfTHPJuyR1oQFHZyP3jItQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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