SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '368574ae8b626799bfd12168f2c19f41f32b7ffd98b88f1e2f1732847cc228d5' 
  AND token = 'GAqvsC+50KFc6RM31AmK9QxzEEPGIKX/5x53TvFSLcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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