SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26b3519024319a0d03ce0559c6fc7a4b1343f60a7facf60c498c12050dc24545' 
  AND token = 'zci4OGkuDwrZQSr4LeF0/ysdHWn47fJe/d3koYaB4ZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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