SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb9b5e391f0dbd886b900479b778d9e93ea4a1370da9644e07fb4e298482952f' 
  AND token = 'uOFgJHSevjnLqE9GFTFMABF/55OyuhS1ezKBLKf0VrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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