SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61e08752be885c0ab10db72da4977de2876b18b064b553bc18ea6d9c9170f464' 
  AND token = 'gHqkn0RXZIu3QtUFogrqf8STotQKumGiaiHbi2XmLoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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