SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '94f29bfe1a26d3470253f840898dcc3dfbea21201c5ac073afb8c35eb12f153e' 
  AND token = 'fW9F0uJZ7CEtub8Rfv8sLvSr+IitmMTUXuAZ9+jh618=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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