SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf39509f8579a634ae37d216bef3bb30d5d6aececb16e80e72a7e554ecfe2d74' 
  AND token = 'bD7lSwrWP8iW03314DK0pPG8TQARWKgn4AsMfBgVtos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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