SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0824e144c4a186e6f9014466bec4724063e47c484ea6c51fbedd62eee08786bc' 
  AND token = '5MTSZYRgiqn83nAobo/TDBORGdCf99+pjqNLTuDqqi4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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