SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '336fcd7d47faf9fc0ac9b445d5e7fea20b19f3b0ccd8656c515c093f88c2036d' 
  AND token = 'ZClQs/IsOwjVxvWU5ehKP5NoBLU1dNLgLl11X3WiNq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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