SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e4338d75805306e307f0e5e61bbcfdf78ea2cb627d48b44cb8bd005b4884733' 
  AND token = 'tkw/DxvT1YQTdQUCyvz+KMbgfoJeIPMuDM4DPdAnm24=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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