SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0123f4040a525264d2ca71965438f76fb751d0ed6238409b36807b1de749d3fe' 
  AND token = 'ByjPoDEubfgVkNJRGVJz4lBDdYelJOkGV5sxBldG0e4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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