SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c19153d18168d1158556cec2d20f3e0aa243b79743845fd3059ca8b54265ed01' 
  AND token = 'LbZAj/8RL7+FtgEZN+ckNUWdTcWx6VpuoOK1Hc8QhG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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