SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '422366a20c84049864526098b06b76789333a0f791f4aed60b1fcbc6bd22db73' 
  AND token = 'G0LrcjWVoMsCsShKubVmy6VKwtq1RCGOCYMPsdHueJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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