SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5093b77ec9f60273fabda0cea72ffae00300b5dac14105381cc84ca06978a2f8' 
  AND token = 'qXrwXiHHJkPzAHBwssMUQr/FzkUm4I7zlMo36vR/G3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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