SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '302edbfa30d7827fcb3b1a34b72707b67ffeb671853f2a082e364210000d0a85' 
  AND token = 'YGbvzgawdAlW/rgfMkQTRA/9Os2mDFg++X6lnZmLvkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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