SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '206fe3cbd7ba8a5f2455ce6f46908b6cd70be3418965b2c664d549b6db62dc20' 
  AND token = 'T9JQNrNOnex9ySPyxTkZf3ybZrbjuSOn123cifConXw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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