SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e2b59cf4a20e72a32ef26999897d1392a016294ded92205ade10bdbbc1f6be1' 
  AND token = 'XMBhZypepmsVqKWizYuYNK64aGPJTNyT6ImhNWUvyJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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