SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a8c92f5facec7b53d89615d61ec020f1732fe975b9802d6320dc7794d0103d6' 
  AND token = '6gfV3z3h9LYl7zBifZeDO4vRqM132s5XQZy/yGGe+4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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