SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cb4c0e490fec1e24575dc9ab50d254dd64ee6b299bc6a5cc0a5d889e8190bb5' 
  AND token = 'x2p9RPIkTe+F4YgV9m9cmlpZziwWw3mTvwCW8hMHss4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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