SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4403d74bd1825faad0e6e49425d33efcfbccbcf1f75e225bfb6a43323b1495c' 
  AND token = 'UPS9rdqnptPuzvNgt8PrLJtCygVlVO6XKDvUbyPiJPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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