SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51bd0c4dcdc8135c2687a85208247938ac5411a701f54fad8758b32cdf55db0f' 
  AND token = 'tPDry46qQLsw/RFzXgetDfRa3+dlJRdHOXwNBIc6omU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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