SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57f9c57938aab1d8bde505384b00b72d7b9f0f4a9ab53011324fe086c1f46f9b' 
  AND token = 'lm6svKxpoTsyhPAYuuBcSjvDU5jXxWaF81xgsv8HKY4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}