SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c0a16e532f3fb8c968ab626fd8457943495aef051568764701c78b343fd2352' 
  AND token = 'BJfZXmnZBwwjFDCOqz9skCBrn8WeCFupSJ+AUi2+yLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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