SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50b5d1b5b983fa8360ede26eae7e3afff956ad94c984f542029385513562bd9c' 
  AND token = 'rZxIRx7XKGICicp//5FU94VlIDO7DFQs4K/Cku3LPzw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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