SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e53d8184a778b5fab2029763c5a4391930acc023acf74af563ca45513dc9c0bb' 
  AND token = 'Os3nfLwTYjEbTude/h07FgwPL89UYoWRTgbNVMFfe7I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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