SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7763e03dc3372da18404fd729ba0776ec620a24b9ffb18b457d6fedcf1e655d' 
  AND token = 'IrqKnS2A/ccvw0ox5bY40OgQBoZMr49puJZAVksurGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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