SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62649115994e175dad379706f13307956088bcb9b01da3c8da1ae591090dfecb' 
  AND token = '4pTp8ZuLLh0tA0zyNcgHPNOjsIaqUPfUTtjR8vjcJPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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