SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bf10aad5db485497cab0dcbe73863a0caa38e3d6b0c41fa0d7da4112d099e56' 
  AND token = 'ub2gZPj/RIAxBwbKTdy+/Ous3bjIUjSDZuoznkO23Gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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