SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cdb81a2966c1ce7634bf57056d43841232f573af23075e12901102df5a5636bc' 
  AND token = 'WaiLQHh5OpFKOTx4fatpubbPcM6TfSqNuEhWYkZIuM8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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