SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '089661404be900b3ec5a294849e11150b35ccded9dc21e40768cdfc397555b41' 
  AND token = 'yHEDHSvkws1Sm+mxRSVKM6B+W+ylDPEZyOIrSRdcBcA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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