SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f655f1c4b143ec2e3030f7feb724589d5d810e59d87a7d17bbfd93f42888295a' 
  AND token = 'rx2c81mqCYm6DOLG8BCWWfk+nYh+niK0wx/AVvnOCSE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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