SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6520a218e29991c241c23b2b589c8f363ebea31469679fb7f25baf9354dbf855' 
  AND token = 'tAhL58S+qEc+sop/qDTY5qzBZt+DYUQh/hfVjvoSKmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}