SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '969028fab5822c91c27e191af366157fb3c60f258a8fa81a575e46b41b16309a' 
  AND token = 'KJAAQBLl2SN7Pe95i+RrxfyMro2dH6eKzDAwW04wx8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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