SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ec07af17accdacf33915abaf1bfeebeaf49edb9a2e7872b6443494959e03f51' 
  AND token = '1oRcuGrmmLOJfWyamaljmrnSx0JqjGZKNJCZoc9wBKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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