SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e7e7fcf8554ba71a09d71a5838ec643445a3aeca78bf71d4aedcad980512e25' 
  AND token = 'WaTusRNnFy1xFy4NVGBhYdyVv55NAutOJcge6znqBwY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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