SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8172a1e15eaab96c83eb9c5983975badd09bb772ffda721067eedcca4cb8163c' 
  AND token = 'kk/fAGL+GDlpZjrr+6CcnzKwsAmTA9azSLvtW6cpQBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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