SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ab42a6ad5c4b7377937c75855ac133a4e04c31f7beed1978d9e26cd363540641' 
  AND token = '9KQzmuMUyMnZIucl1OZr88egWUA6PYAl6Z2ktzlJ12M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}