SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '125305b35eb5a6e9e8ec4587f6f3011fad18b902e2ebb88061d648ceca349b51' 
  AND token = 'bPdpCHJ3hx8t3rG0yZyxeKQp1iJ6J7aXQzS3l1wQs8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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