SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7552cef60225012e9d3d118168d39ac0eb730487531a88ed21894362288a2155' 
  AND token = 'E3BSjCfpAUQwNOBoIfALBfkdD6jf8wzTvzh7z7wKez0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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