SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4256a6cbd0cce376359eed1e8bbc9fbf2efd8e0879249d85b615a288ee386b78' 
  AND token = 'ZYSGQINZ7/HYZR1IuZKZiwvgiWofYrwQ9BgWvZnLTG8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}