SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c2f376642bd68c3d3f12c4ee601ede8d316850b364e86b85f38926198b72fb0' 
  AND token = 'yx67OE4IXEMXVghHIR3MXAwOA6NJQo6F20umbcq7RAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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