SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73b2e250659d74f2d3b622a2ac590fc44aad117c80d06dcd31f78bf28bc58800' 
  AND token = '2aIq+w0YLVziTpNxRXNS07gP3QuzJmjhdfD95nBW+N4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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