SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e27dc84aefcc7aa5f6f035cb944c3711cd1d4fdec88a83c94e9af22f12c4e5e' 
  AND token = 'xM80cq/T+2yVLTKwV3F4RS3Y08idot6p8zYDI7/Ztg0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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