SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '021cf615fca5a1e45ddb4ad921d11c8da16ea0dfc2e73321c20620a04ab2b0ef' 
  AND token = 'qunyruEoZdfofRVWh3+UfO40iY/rXxRYEWii2CUVaLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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