SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '771b0aa3f19258149f3d1b35790a49dc51d58c7e4de2bbf23dccb8a5f2597e20' 
  AND token = 'MpHAJdajWNcLg407RVzrKAXvZr5B4zAY2YnJkG2h/z4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}